Comment #8 on issue 1694 by smichr: solve has many issues with fractions http://code.google.com/p/sympy/issues/detail?id=1694
In the segment to check if Q != 0, you simply test Q without expanding or simplifying. But simple exressions like the following will not test to be zero unless you expand them: ### >>> eq -a + a*(1 + b) - a*b >>> eq.is_zero >>> eq.is_nonzero ### At least expanding would be a step in the right direction, I think. I don't think it will solve every problem, but it will solve more than doing nothing. I also wonder if going through an inversion process (like what is used in solve), trying to solve for any one of the variables in the expression (or all in turn), might work. At some point the expression should(?) become simple enough that you find that 0 == 0. If there are no variables in the expression (and there are no Real's in it) will sympy ever have a problem ascertaining that the expression is 0? Let's see... ### >>> eq -a + a*(1 + b) - a*b >>> eq.subs(a,sqrt(1+sqrt(3))) (1 + 3**(1/2))**(1/2)*(1 + b) - (1 + 3**(1/2))**(1/2) - b*(1 + 3**(1/2))**(1/2) >>> _.subs(b,1/(1+sqrt(3))) (1 + 3**(1/2))**(1/2)*(1 + 1/(1 + 3**(1/2))) - (1 + 3**(1/2))**(1/2) - 1/(1 + 3* *(1/2))**(1/2) >>> z=_ >>> z.expand() 0 ### sympy didn't recognize that the intermediate forms were 0 but once expand was used then it did. /c -- You received this message because you are listed in the owner or CC fields of this issue, or because you starred this issue. You may adjust your issue notification preferences at: http://code.google.com/hosting/settings --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sympy-issues" group. To post to this group, send email to sympy-issues@googlegroups.com To unsubscribe from this group, send email to sympy-issues+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sympy-issues?hl=en -~----------~----~----~----~------~----~------~--~---
